(1) Field of the Invention
This invention relates to glassy phosphate detergent additives and to processes for preparing detergent compositions containing glassy phosphate additives.
(2) Prior Art
The utility of glassy phosphates as an adjuvant to soap has been recognized for years. (U.S. Pat. No. 1,956,515 to Ralph E. Hall, Apr. 24, 1934.)
Glassy phosphates are known to have the property of sequestering ions of calcium, magnesium, and other polyvalent metals, and of deflocculating or dispersing certain solids, e.g., clay soils. However, they have the undesirable property in aqueous solution of being hydrolyzed to less desirable and sometimes objectionable lower phosphates, with corresponding loss of their useful properties. Thus, the incorporation of glassy phosphates into detergent compositions without hydrolysis has been beset with difficulty. For example, U.S. Pat. No. 2,568,110 to Irving Beiley et al, Sept. 18, 1951, attempted to overcome this problem by admixing a concentrated aqueous solution containing 20% to 65% glassy phosphate with a substantially hydratable salt. This approach, typical of the prior art, sought to compensate for the decomposition or hydrolysis by adding additional glassy phosphates to the composition. Specific uses of the glassy phosphates of this invention are also found in U.S. Pat. No. 3,896,056 issued July 22, 1975 to Benjamin and Connor, and the copending application of Francis, Carson and McKay, Ser. No. 587,451 filed June 16, 1975, both of which are herein incorporated by reference.
Throughout the specification and claims percentages and ratios are by weight and temperatures in degrees Fahrenheit unless otherwise indicated.